To play tennis well, your legs must provide a strong, stable base of support.

Ground strokes and volleys both start with a split-step, during which the muscles of the legs absorb the shock of touching down on the ground, and are typically followed by an explosive movement in one direction or the other. When a player is pulled wide for a shot, he must recover toward the center of the court. If his legs are strong, he can recover faster and more often without fatigue.

The box jump is a great plyometric drill that focuses on training your legs for explosive movements, which are required quite often during the course of a match, such as when changing direction. In addition, training the legs for explosive power helps develop a better tennis serve: Your legs play an important role in transferring force from the ground up to the rest of your body.

Note: The box jump is an advanced drill. Incorporate it into your training program only after you’ve established an appropriate strength base for your legs.

The Box Jump:

1. You will need a sturdy box that is 12 to 42 inches high, depending on your ability. Stand facing the box, approximately one to two feet from it, with your feet shoulder-width apart.

2. Move your elbows toward your hips by squeezing your shoulder blades together. Maintain a 45-degree bend in the elbows. Raise the upper back and keep the feet off the floor.

3. Return to the starting position and repeat. Repeat.

Variation: Single-leg box jump

1. This more advanced version of the box jump has you jump- ing with only one leg. This jump requires a considerable amount of strength and coordination and is a highly advanced exer- cise; it’s recommended only for advanced players.

2. The single-leg box jump may be performed with either leg. Use a box that is lower than the box used for the regular box jump—one that is about 4 to 16 inches high.

3. Execute the rest of the exer- cise in the same manner as the two-legged jump.